Moscow has told the US to reduce the number of its diplomatic staff in Russia to 455 people, and is also halting the use of embassy storage facilities in the capital, according to the Russian Foreign Ministry.

The retaliatory move comes after the US Congress approved new sanctions against Russia.

“The Russian side is suspending the use of all storage facilities on Dorozhnaya Street in Moscow, and a cottage in Serebryaniy Bor by the US Embassy in Russia as of August 1,” the ministry said in a statement.

The number of US diplomatic service staff in Russia should be reduced to equal the number of Russian diplomats in the US by September 1, Moscow says.

“This means that the total number of personnel involved in the American diplomatic and consular institutions in the Russian Federation is reduced to 455.”

Russian President Vladimir Putin has approved the move, according to his spokesman, Dmitry Peskov.

Russia has also threatened to resort to additional retaliatory measures in case of new moves by Washington to reduce its diplomatic corps.

“In the case of new unilateral actions of the US authorities to reduce the number of our diplomats in the US, it will be followed by a tit-for-tat response,” the Foreign Ministry stated.

“We reserve the right on other mutual measures, which can affect US interests."

On July 14, Moscow warned that it was running out of patience in light of the stalemate that followed the closure of two Russian diplomatic compounds in the US, and mentioned possible retaliatory measures including the expulsion of diplomats.

“We have something to retaliate with: the personnel of the US embassy in Moscow greatly exceeds the number of our embassy staff in Washington,” Russian Foreign Ministry spokesperson Maria Zakharova stated.

Russian diplomatic property was confiscated by the Obama administration in 2016, in response to alleged Russian meddling in the US election. The US also expelled 35 Russian diplomats and denied Russian diplomatic staff access to the New York and Maryland compounds.

The Russian Foreign Ministry strongly criticized the latest package of sanctions approved by US lawmakers on Tuesday. The bill targeting Russia’s major defense, mining, shipping and railway industries is yet to be approved by US President Donald Trump. However, Moscow sees the Senate approval of the new round of sanctions as an almost final decision, according to Peskov.

“The United States insistently implements rough anti-Russian sanctions one after another under the absolutely far-fetched pretext of Russian meddling in their internal affairs,” the Russian Foreign Ministry stated, adding that such moves violate international law and UN principles.

“The US makes decisions on illegal sanctions against the Russian Federation, seizes Russian diplomatic property, which is formalized in legally binding bilateral documents, Russian diplomats are expelled from the country. This clearly violates the Vienna Convention on Diplomatic Relations and generally accepted diplomatic practice.”

According to former Greek ambassador Leonidas Chrysanthopoulos, initially promising signs of a recovering Russian-American relationship are being derailed by Congress, which is still stuck in a Cold War mentality.

“It’s to the credit of Russia that they waited so long to take these measures. They gave an opportunity to the new administration to ameliorate relations between Washington and Moscow. In spite of the fact there was a good meeting between Trump and Vladimir Putin in Hamburg, we see that the administration and Congress still insist on this hardline policy,” Chrysanthopoulos told RT.

“I think on the Syria issue, it’s not going to affect it very much because Lavrov has very good contacts with his American counterparts, and what they’ve worked out until now has been effective.”

“I hope it will not affect the other issues. Of course, it’s also up to Congress to assume their responsibility. They are treating the Russian Federation as if it was the Soviet Union, and they have to understand it is not the Soviet Union. This is what they have to put into their minds!”

In a phone call with US Secretary of State Rex Tillerson, Russian Foreign Minister Sergey Lavrov said that Russia was fully prepared to normalize relations, but was forced to act in the face of Washington’s hostility, including sanctions, the expulsion of diplomats and the seizing of diplomatic property. Lavrov added that Russia opted for a restrained response to help Washington realize its mistake, and to emphasize that relations can only continue on the basis of mutual respect. Bilateral cooperation will still continue on the most important aspects of the international agenda, Lavrov said.